1. Field of the Invention
The present invention generally relates to a printer apparatus, and more particularly to a thermal printer apparatus having a first module detachably attached to a second module in which a fixed blade in the first module and a movable blade in the second module together form a cutter for cutting a paper printed by the printer apparatus.
2. Description of the Related Art
A thermal printer apparatus having a function of automatically cutting a continuing sheet of paper is, in general, mounted to portable terminals such as a POS terminal or a ticketing terminal.
A conventional thermal printer apparatus having an automatic sheet cutting function has a thermal printer main body including a thermal head, a platen, and a motor, wherein the thermal printer main body is attached to a separate cutter apparatus. The cutter apparatus has a fixed blade, a movable blade, and a motor for moving the movable blade.
In many conventional thermal printer apparatuses, the height of the thermal printer main body is required to match with that of the cutter apparatus, which causes difficulty in forming a thin sized thermal printer apparatus. Therefore, the demand for a thin sized portable terminal could not be satisfied.
Under this circumstance, the applicant of the present application proposed a thermal printer apparatus 10 having a cutter part, wherein a first module 11 is detachably attached to a second module 20. FIGS. 1A through 1C are schematic drawings showing the thermal printer apparatus 10. FIG. 1A shows a state where the second module 20 is separated from the first module 11. FIG. 1B is a side view of the thermal printer apparatus 10 having the second module 20 attached to the first module 11, and FIG. 1C is a plan view of the thermal printer apparatus 10 having the second module 20 attached to the first module 11. As shown in FIG. 1C, X1-X2 indicates the width direction of the thermal printer apparatus 10. As shown in FIGS. 1A and 1B, Y1-Y2 indicates the length (longitudinal) direction of the thermal printer apparatus 10, and Z1-Z2 indicates the height direction of the thermal printer apparatus 10. The first module 11 includes a thermal head 12, a head-urging planar spring member 13, a fixed blade 14, a blade-urging planar spring member 15, a lock member 16, and a pulse motor (not shown). The lock member 16 is urged in a clockwise direction by a spring member. The second module 20 includes a platen roller 21 and a movable blade 22. The fixed blade 14 and the movable blade 22 together form a cutter 30 (FIGS. 1B and 1C), which is referred in greater detail below. As shown in FIG. 1C, the fixed blade 14 has a straight shaped blade part 14a, and the movable blade 22 has a V-shaped blade part 22a. In addition, finger parts 22b, 22c are disposed on both ends of the blade part 22a. 
The first module 11 is attached to a main body of a portable terminal, and the second module 20 is attached to a rotatable openable lid. In a final stage of rotating and closing the lid, the lock member 16 is temporarily depressed. When the lid is completely closed, an axis 23 of the platen roller 21 becomes engaged with the lock member 16, the second module 20 becomes coupled to the first module 11, and the platen roller 21 abuts the thermal head 12, thereby obtaining an initial state of the cutter 30 in which the finger parts 22b, 22c of the movable blade 22 overlap with an upper part of the fixed blade 14, as shown in FIGS. 1B and 1C. In the final stage of closing the lid, the finger parts 22b, 22c contact against the fixed blade 14 to cause the fixed blade 14 to flex the blade-urging planar spring member 15 and to move toward direction Z2. In this state, the urging force generated by the blade-urging planar spring member 15 serves as a force required for cutting paper disposed between the movable blade 22 and the fixed blade 14.
That is, the movable blade 22 is moved to a position where the fixed blade 14 is depressed against the blade-urging planar spring member 15, so that the axis 23 of the platen roller 21 becomes engaged with the lock member 16. This procedure of closing the lid of the portable terminal requires an inconvenient operation of firmly applying a considerable amount of force F1 to the lid.
Furthermore, in a case where the lid is inadvertently closed in an incomplete manner, the axis 23 of the platen roller 21 cannot sufficiently engage with the lock member 16. This may cause the lid to undesirably open during operation of the thermal printer apparatus 10.